The present invention relates to a tab attaching device, used in equipment for preparing paper rolls for web pasting, which is included in a printing system for newsprint and the like. The tab attaching device automatically attaches one side of a tab to the outer surface of the web's leading end so that the web's leading end, which is cut into a set shape (for example, V-shape), may be fastened to the outer surface of a paper roll.
As shown in FIG. 14, as a paper roll is continuously fed to a rotary press 51 from an expiring web 52a of a first paper roll 52b a trailing edge of the expiring web 52a is pasted, by means of a pusher 53, to a leading end of a second paper roll 52c which is rotated at a rate peripherally equal to the rate at which the expiring first paper web 52a is being fed. In FIG. 14 are shown a reel stand 54 and a drive device 55 for the paper rolls 52b, c, and d.
The automatic pasting of the paper rolls requires that the leading end of the second paper roll 52c be prepared beforehand for the adhesive pasting. Generally this preparation is made by a manual procedure in the following manner: As shown in FIG. 15, the leading end of a paper roll 52c is cut into a basically V-shaped portion whose tip is attached to the outer surface of the paper roll 52c with a tab 56, and pressure sensitive adhesive double coated tape 57 is attached to the outer surface of the V-shaped leading end to form a plurality of adhesive portions.
The manual process required to carry out all of this pasting preparation has been very inefficient and costly. Another problem has been a loss of paper because the manual removal of the peripheral layer is liable to damage inner layers.
Accordingly, various types of automatic devices for web pasting have been developed to solve the problems incidental to the manual preparation for web pasting. Japanese Provisional Publication No. 1986-12561, and U.S. Pat. Nos. 4,685,392 and 4,683,022 exemplify these types of automatic devices for preparing web pasting.
The automatic device for preparing web pasting in Japanese Provisional Publication No. 1986-12561 is comprised of a stand to support a paper roll in such a manner as to allow it to rotate in any direction, a table board on which the web's leading end is placed and supported, and a main preparing device which produces a basically V-shaped incision as well as web pasting adhesive portions and carries out tab attachment. The above-mentioned device automatically operates according to the following procedure: feeds the web's leading end onto the table board, produces a basically V-shaped incision and adhesive portions for web pasting at the web's leading end, cuts and removes the web's leading end along the V-shaped incision, attaches a tab's trailing edge to the basically V-shaped leading end of a paper roll, and attaches a tab leading edge to the outer surface of the paper roll.
As shown in FIG. 16, a prior art main preparing device 58, which forms an important part of a prior-art automatic preparing device for web pasting, is comprised of a housing case 59, a paper feeding device 61 for moving the web's leading end placed on a table board 60 in a set direction, a tape supplying device 63 for feeding a strip-shaped tab 62 of a set length to a top surface of the web's leading end, a cutter device 64 for producing the separating incision on the web's leading end, and an adhesive portion forming device 66 for forming a quantity of adhesive portions by attaching pressure sensitive adhesive double coated tape 65 to the web's leading end. The main preparing device 58 is held on a guide rail (not shown) which is supported so that it may rotate in any direction. At the same time, a front edge of the housing 59 is held so that is may move in a vertical direction.
As shown in FIGS. 17 through 19, when the tab 62 is attached to the leading end of a paper roll 52 by using the main preparing device 58, the basically V-shaped leading end of the paper roll 52 is supplied with the tab 62 of a set length by the tape feeding device 63. One end of the tab is fastened to the V-shaped leading end while the pressure sensitive adhesive double coated tape 65 is also placed thereon by the adhesive portion forming device 66. The web's leading end is rewound and the other end of the tab 62 is fastened to the outer surface of the paper roll with the pressure sensitive adhesive double coated tape 65, which is fed from the adhesive portions forming device 66, being thereon. The above-mentioned procedure presents a problem of inefficiency, as much time is required to attach the tab 62. Furthermore, the tab 62 placed on the web's leading end may slip or be blown off. This may cause incorrect attachment of the tab 62; it may not attach at the desired position of the web's leading end.
In U.S. Pat. Nos. 4,685,392 and 4,683,022 a tab attaching device is placed under a table. A tab prepared beforehand is pushed upwardly through a guide hole in the table, and the one edge of the tab is pressed and fastened to the underside of the web's leading end.
In the above-mentioned U.S. Patents, a protective-coating film removing roller contacts a tab which is retained by means of a vacuum suction. Since the roller removes the protective-coating film from the tab, a slight deviation of the contact pressure between the roller and the protective-coating film may lead to an error in protective-coating film removal or damage to the tab. Tab attachment may be disrupted.
Furthermore, the web's leading end surface needs to be pressed downward by a pressing roller of a main preparing device during tab attachment, while the tab is pressed upwardly toward the underside of the web's leading end. It is rather difficult to fix the interval between the two movements: pressing the tab upward and pressing the web's leading end downward by means of the pressing roller. An incompatible interval may result in an error in tab attachment.